"Do what you can, with what you have, where you are."

"It is not the critic who counts; not the man who points out how the strong
man stumbles, or where the doer of deeds could have done them better.
The credit belongs to the man who is actually in the arena, whose face is
marred by dust and sweat and blood; who strives valiantly; who errs, who
comes short again and again, because there is no effort without error and
shortcoming; but who does actually strive to do the deeds; who knows
great enthusiasms, the great devotions; who spends himself in a worthy
cause; who at the best knows in the end the triumph of high achievement,
and who at the worst, if he fails, at least fails while daring greatly, so that
his place shall never be with those cold and timid souls who neither know
victory nor defeat."  - Theodore Roosevelt

(with thanks to Gwyn from The Actor's Market)